In a rolling mill which rolls a material to be rolled, the plate thickness accuracy on the delivery side of the rolling mill is a great factor which has an influence on the quality of products. It is known that in such a rolling technique a change in the oil film thickness of oil film bearings of backup rolls exerts an influence on the plate thickness accuracy on the delivery side of the rolling mill. For this reason, in order to improve the plate thickness accuracy on the delivery side of the rolling mill, techniques for compensating for a plate thickness change on the delivery side of the rolling mill resulting from the above-described oil film thickness of the oil film bearings have hitherto been studied.
For example, as conventional arts there have been proposed techniques for determining rolling position in consideration of the oil film thickness of oil film bearings in order to cause the plate thickness on the delivery side of the rolling mill to approach a target plate thickness (refer to Patent Document 1, for example).    Patent Document 1: Japanese Patent Laid-Open No. 58-212806